adding index stats collection to n1ql tests
adding index stats collection to n1ql tests

Change-Id: I3f73ad8694452d8e03c4da7d976dfb7938ff81e1
Reviewed-on: http://review.couchbase.org/c/perfrunner/+/149095
Tested-by: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Bo-Chun Wang <bb86fd206c9c35341feb9b50e74a74a83e254d63@couchbase.com>

couchbase/perfrunner,couchbase/perfrunner,couchbase/perfrunner,couchbase/perfrunner,couchbase/perfrunner,couchbase/perfrunner